an abrupt change in the course of a stream that forms the boundary between two parcels of land resulting in the loss of part of the land of one landowner and a consequent increase in the land of another (noun.event)

change (a compound) by increasing the proportion of the electronegative part; or change (an element or ion) from a lower to a higher positive valence: remove one or more electrons from (an atom, ion, or molecule) (verb.change)